As to the outward appearance of this Vegetative body, they are so usuall everywhere, that I need not describe them, consisting of a soft and porous substance, representing a Lock, sometimes a fleece of Wool; but it has besides these small _microscopical_ pores which lie between the _fibres_, a multitude of round pores or holes, which, from the top of it, pierce into the body, and sometimes go quite through to the bottom. I have observ’d many of these Sponges, to have included likewise in the midst of their fibrous contextures, pretty large friable stones, which must either have been inclos’d whil’st this Vegetable was in formation, or generated in those places after it was perfectly shap’d. The later of which seems the more improbable, because I did not find that any of these stony substances were perforated with the _fibres_ of the Sponge. I have never seen nor been enform’d of the true manner of the growing of Sponges on the Rock; whether they are found to increase from little to great, like Vegetables, that is, part after part, or like Animals, all parts equally growing together; or whether they be _matrices_ or feed-baggs of any kind of Fishes, or some kind of watry Insect; or whether they are at any times more soft and tender, or of another nature and texture, which things, if I knew how, I should much desire to be informed of: but from a cursory view that I at first made with my _Microscope_, and some other trials, I supposed it to be some Animal substance cast out, and fastned upon the Rocks in the form of a froth, or _congeries_ of bubbles, like that which I have often observ’d on Rosemary, and other Plants (wherein is included a little Insect) that all the little films which divide these bubbles one from another, did presently, almost after the substance began to grow a little harder, break, and leave onely the thread behind, which might be, as ’twere, the angle or thread between the bubbles, that the great holes or pores observable in these Sponges were made by the eruption of the included _Heterogeneous_ substance (whether air, or some other body, for many other fluid bodies will do the same thing) which breaking out of the lesser, were collected into very large bubbles, and so might make their way out of the Sponge, and in their passage might leave a round cavity; and if it were large, might carry up with it the adjacent bubbles, which may be perceiv’d at the outside of the Sponge, if it be first throughly wetted, and sufferr’d to plump itself into its natural form, or be then wrung dry, and suffer’d to expand it self again, which it will freely do whil’st moist: for when it has thus plump’d it self into its natural shape and dimensions, ’tis obvious enough that the mouths of the larger holes have a kind of lip or rising round about them, but the other smaller pores have little or none. It may further be found, that each of these great pores has many other small pores below, that are united unto it, and help to